Ring rolling tool



May 14, 1968 J. ROZHDESTVENSKY ETAL 3,382,693

RING ROLLING TOOL Filed March 2, 1965 2 SheetsSheet l INVENTORS JURY LVOVICH ROZHDESTVENSKY VICTOR VICTOROVICH SIVHRNOV ATTORNEYS y 1968 J. 1.. ROZHDESTVENSKY ETAL 3,382,63

RING ROLLING TOOL 2 Sheets-Sheet 2 Filed March 2, 1 965 INVENTORS JURY LVOVICH ROZHDESTVENSKY VICTOR VICTOROVICH SMIRNOV By mmygw *WQ ATTORNEY s United States Patent Office Patented May 14, 1958 3,382,693 RING ROLLING TOOL Jury Lvovich Rozhdestvensky and Victor Victorovich Smiruov, Moscow, U.S.S.R., assignors to Vsesojuzny Nauchno-Issledovatelsky Koustruktorsko-Tekhnologichesky Institute podshipnikovoi Promyshleunosti, Moscow, U.S.S.R.

Filed Mar. 2, 1965, Ser. No. 436,608 2 Claims. (CI. 72-87) ABSTRACT OF THE DISCLOSURE A ring rolling tool using a hollow roll against the inner surface of which the ring is rolled by an inner roll, and side rolls rotating on an axis exterior of the hollow roll and tangential to the inner roll, and means to move the hollow roll to one side so that a flash formed between the inner roll and the side rolls will be cut off by the side rolls.

This invention relates to ring rolling machines, more particularly to the tools thereof for rolling rings, including the outer races of anti-friction bearings.

It is known to use tools for the so-called closed ring rolling which comprise a hollow roll accommodating an inside roll so that a heated ring blank is placed between the two and rolled by virtue of said two rolls rotating in the same direction and moving radially in relation to each other. This permits the rings so worked to acquire the desired contour of the inside surface and be chamfered at four edges.

Excess metal present in the rings due to a dilference in the weight of the ring blanks is formed into side fins. Extraction of the rolled rings is accomplished by making the hollow roll split in the end plane.

With the use of the aforesaid tool, the rolled rings approach the final shape and dimensions. However, during the final stage of rolling a considerable axial stress is set up in the rings, which, accompanied by intense cooling of the blank, causes high unit pressures on the tool. Removal of the side fins necessitates additional cutting operations such as turning in a lathe.

It is also known to use tools for the so-called open ring rolling which comprise two rolls on one of which the ring blank is put to be rolled by the action of said two rolls rotating in the opposite directions and moving radially in relation to each other.

With this method of rolling, it is possible to obtain rings with the desired contour of the outer and inner surfaces and chamfers at four edges. Open rolling gives rise to comparatively low unit pressures on the tool. However, difference in the Weight of the ring blanks results in inaccuracy of the diametrical dimensions of the rolled rings.

The object of this invention is to eliminate the aforementioned principal disadvantages.

A further object of this invention is to devise a ring rolling tool that will permit substantial reduction in unit pressures on the tool and provide for obtaining the desired ring cross section with high accuracy in dimensions, the side fins being removed directly during the rolling process.

According to the present invention, there is provided a ring rolling tool for use in a ring rolling machine, which tool comprises a positively driven hollow roll and another roll disposed within said hollow roll so as to form a space to accommodate a ring blank to be rolled by the action of said tool, with said two rolls moving radially in relation to each other, the excess metal existing due to a difference in the weight of ring blanks being formed into side fins. The outer surface of the hollow roll bears on two rolls and is less in width than the ring being rolled, due to which the hollow roll forms only the center portion of the ring blank outer surface. The hollow roll is sandwiched be tween side rolls which are mounted on a shaft parallel to the axes of the hollow roll and the inner roll and serve to form the outer chamfers of the ring.

In order to provide for removal of fins in the process of rolling, the side rolls, hollow roll and inner roll are disposed so that the axis of the side rolls is off the plane passing through the axes of the hollow and inner rolls.

The use of the tool claimed herein permits production of precision ring-shaped articles, e.g. outer races of anti-friction bearings, with comparatively low unit pressures in rolling and small allowances for subsequent cutting, thus ensuring economy in metal and labour.

For a further understanding of the present invention reference is to be had to the following description and the accompanying drawing, wherein:

FIG. 1 shows an axial section through the tool interacting with the blank;

FIG. 2 is a section on line 22 of FIG. 1 on an enlarged scale;

FIG. 3 shows a section of the flash as it is being removed, ring 1 being moved to one side;

FIG. 4 is a fragmentary section on line 4-4 of FIG. 3; and

FIG. 5 is a fragmentary section on line 5-5 of FIG. 3.

The ring rolling tool comprises a hollow roll 1 (FIG. 1), an inner roll 2 and side rolls 3. The inner roll 2 is disposed within the hollow roll 1 so as to provide a space to accommodate a ring blank 4.

The side rolls 3 are coaxially mounted on the pressure roll 5 of the ring rolling machine and positioned on either side of the hollow roll 1.

The width h of the hollow roll 1 is less than the width H of the ring blank 4, the roll 1 serving to form the center portion of the outer surface of the ring blank 4.

The side rolls 3 serve to form the outer chamfers 6 of the ring blank 4.

The side rolls 3, hollow roll 1, and inner roll 2 can be so disposed that the axis O O of the side rolls 3 is off the plane passing through the axis O O of the hollow roll 1 and the axis 0 -0 of the inner roll 2, which disposition permits removing the side fins in the process of rolling the ring blank 4.

The hollow roll 1 is driven by the pressure roll 5 by the action of friction, being forced towards the inner roll 2. Under these conditions relative radial movement of the hollow roll 1 and the inner roll 2 occurs, due to which excess metal present because of a difference in the weight of the ring blanks is formed into side fins 7.

The side faces of the side rolls 3 guide the hollow roll 1, while the working surfaces 8 of the side rolls 3 form the outer chamfers 6 on the ring blank 4, the contour of the ring inner surface being formed by the inner roll 2. During the final stage of rolling the outside diameter of the ring blank is confined by the inside diameter of the hollow roll 1.

With this design of the tool, during the final stage of rolling the side rolls 3 may be brought up against the inner roll 2 as to increase the accuracy of rolling and to compress the flash 7 to a very thin section.

The removal of the flashes 7 is seen diagrammatically in FIGURES 3, 4 and 5. In FIGURE 3 the flash only is shown in section. The side rolls 3 rotating clockwise and the hollow roll being moved to the right under the influence of the roll 9, the flash then is pushed down as seen in FIGURE 5. Then, as the shaped work piece passes to the location of inner roll 2, the flash is bent upwardly as seen in FIGURE 4. As pointed out above, when the side rolls 3 are brought against the shaft of inner roll 2 the flash 7 is very thin so it requires very little movement as seen in FIGURES 4 and 5 to remove the flash.

Thus the ring rolling tool described herein performs the so-called semiclosed rolling, which is a combination of the closed method (whereby the center portion of the ring blank outer surface is formed within the hollow roll 1) and the Open method (whereby the parts of the ring blank 4 extending from the hollow roll 1 are formed between side rolls). This combined method provides for removal of side fins in the process of rolling and reduction in the unit pressures exerted between the ring blank and the tool. The latter effect is attributed to the more favorable strain conditions, as compared to the closed method, owing to open rolling of the end portions of the ring blank as well as to the reduction in the heat loss suffered by the ring blank in the event of hot rolling, which reduction results from the fact that the area of contact between the ring blank and the tool is less than in the case of the tools used hitherto for closed rolling.

What is claimed is:

1. A ring rolling tool designed for use in ring rolling machines and comprising: a positively driven hollow roll the width of which is less than that of the ring blank, said hollow roll forming the center portion of the ring blank outer surface; an inner roll accommodated within said hollow roll; a space between said hollow roll and said inner roll serving to accommodate a ring blank to be rolled by the action of said tool, side rolls provided to form the outer chamfers on the ring blank and mounted on either side of said hollow roll on a shaft disposed parallel to the axes and beyond the peripheries of said hollow and inner rolls; means to move said inner and said hollow rolls radially in relation to each other to press a ring blank therebetween, the excess of metal existing due to excess volume of the weight of the ring blank being formed into side fins; and at least one movable support roll adapted to move said hollow roll in a direction normal to its axis whereby said side fins will be cut off.

2. A ring rolling tool designed for use in ring rolling machines and comprising: a positively driven hollow roll the width of which is less than that of the ring blank, said hollow roll forming the center portion of the ring blank outer surface; an inner roll accommodated within said hollow roll; a space between said hollow roll and said inner roll serving to accommodate a ring blank to be rolled by the action of said tool, said rolls being movable radially in relation to each other to press said ring blank therebetween, the excess of metal existing due to excess volume of the ring blank being formed into side fins; side rolls provided to form the outer chamfers on the ring blank and mounted on either side of said hollow roll on a shaft disposed parallel to the axes and beyond the peripheries of said hollow and inner rolls and to one side of the plane passing through the axes of said hollow and inner rolls whereby the side fins are removed in the process of rolling.

References Cited UNITED STATES PATENTS 745,555 12/1903 Aranyi -5 X 3,160,036 12/1964 Ernestus 72-91 X 3,230,606 1/1966 Saito et al. 72-111 X RICHARD J. HERBST, Primary Examiner.

E. SUTTON, Assistant Examiner. 

